/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/
/****************************************************************************
 * tools/cfgpaser.c
 *
 *   Copyright (C) 2007-2013 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <string.h>
#include <stdlib.h>
#include <ctype.h>

#include "cfgparser.h"

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/****************************************************************************
 * Public Data
 ****************************************************************************/

static char line[LINESIZE + 1];

/****************************************************************************
 * Private Data
 ****************************************************************************/

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/* Skip over any spaces */

static char *skip_space(char *ptr)
{
	while (*ptr && isspace((int)*ptr))
		ptr++;
	return ptr;
}

/* Find the end of a variable string */

static char *find_name_end(char *ptr)
{
	while (*ptr && (isalnum((int)*ptr) || *ptr == '_'))
		ptr++;
	return ptr;
}

/* Find the end of a value string */

static char *find_value_end(char *ptr)
{
	while (*ptr && !isspace((int)*ptr)) {
		if (*ptr == '"') {
			do
				ptr++;
			while (*ptr && *ptr != '"');
			if (*ptr)
				ptr++;
		} else {
			do
				ptr++;
			while (*ptr && !isspace((int)*ptr) && *ptr != '"');
		}
	}
	return ptr;
}

/* Read the next line from the configuration file */

static char *read_line(FILE * stream)
{
	char *ptr;

	for (;;) {
		line[LINESIZE] = '\0';
		if (!fgets(line, LINESIZE, stream))
			return NULL;
		else {
			ptr = skip_space(line);
			if (*ptr && *ptr != '#' && *ptr != '\n')
				return ptr;
		}
	}
}

/* Parse the line from the configuration file into a variable name
 * string and a value string.
 */

static void parse_line(char *ptr, char **varname, char **varval)
{
	/* Skip over any leading spaces */

	ptr = skip_space(ptr);

	/* The first no-space is the beginning of the variable name */

	*varname = skip_space(ptr);
	*varval = NULL;

	/* Parse to the end of the variable name */

	ptr = find_name_end(ptr);

	/* An equal sign is expected next, perhaps after some white space */

	if (*ptr && *ptr != '=') {
		/* Some else follows the variable name.  Terminate the variable
		 * name and skip over any spaces.
		 */

		*ptr = '\0';
		ptr = skip_space(ptr + 1);
	}

	/* Verify that the equal sign is present */

	if (*ptr == '=') {
		/* Make sure that the variable name is terminated (this was already
		 * done if the name was followed by white space.
		 */

		*ptr = '\0';

		/* The variable value should follow =, perhaps separated by some
		 * white space.
		 */

		ptr = skip_space(ptr + 1);
		if (*ptr) {
			/* Yes.. a variable follows.  Save the pointer to the start
			 * of the variable string.
			 */

			*varval = ptr;

			/* Find the end of the variable string and make sure that it
			 * is terminated.
			 */

			ptr = find_value_end(ptr);
			*ptr = '\0';
		}
	}
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

void parse_file(FILE * stream, struct variable_s **list)
{
	struct variable_s *curr;
	struct variable_s *prev;
	struct variable_s *next;
	char *varname;
	char *varval;
	char *ptr;

	/* Loop until the entire file has been parsed. */

	do {
		/* Read the next line from the file */

		ptr = read_line(stream);
		if (ptr) {
			/* Parse the line into a variable and a value field */

			parse_line(ptr, &varname, &varval);

			/* If the variable has not value (or the special value 'n'), then
			 * ignore it.
			 */

			if (!varval || strcmp(varval, "n") == 0)
				continue;

			/* Make sure that a variable name was found. */

			if (varname) {
				int varlen = strlen(varname) + 1;
				int vallen = 0;

				/* Get the size of the value, including the NUL terminating
				 * character.
				 */

				if (varval)
					vallen = strlen(varval) + 1;

				/* Allocate memory to hold the struct variable_s with the
				 * variable name and the value.
				 */

				curr = (struct variable_s *)malloc(sizeof(struct variable_s) + varlen + vallen - 1);
				if (curr) {
					/* Add the variable to the list */

					curr->var = &curr->storage[0];
					strcpy(curr->var, varname);

					curr->val = NULL;
					if (varval) {
						curr->val = &curr->storage[varlen];
						strcpy(curr->val, varval);
					}

					prev = 0;
					next = *list;
					while (next && strcmp(next->var, curr->var) <= 0) {
						prev = next;
						next = next->flink;
					}

					if (prev)
						prev->flink = curr;
					else
						*list = curr;

					curr->flink = next;
				}
			}
		}
	} while (ptr);
}

struct variable_s *find_variable(const char *varname, struct variable_s *list)
{
	while (list) {
		if (strcmp(varname, list->var) == 0)
			return list;

		list = list->flink;
	}

	return NULL;
}
